This remarkable post details some of the impossible logistics of deploying the "NIR" and talks about the likely fallout of these failings. If you want to fight the NIR, join NO2ID, the national campaign to stop it.
So adding it all up, from NIR Day 1 for ten years you've got to keep processing people at the rate of 50 per hour at every centre, or one every 72 seconds, each of whom requires a scan of the whole central NIR to avoid multiple registrations, so the database has to be up and accessible every minute of the day to avoid delay.Link (via Charlie)
In the early days it's a nailed on certainty that we'll get failures, resulting in potentially hundreds of people making pointless journeys (say it's down for an hour during a particular day - that's 50 people at each centre having their time wasted, a total of 3500 people). I have no idea of the MTBF for major government IT projects, and they almost certainly won't tell me on the usual 'commercial confidentiality' grounds. What I can do is provide some figures based on possible percentage reliability and estimate the number of people inconvenienced per year and the kind of reliability that would be required *from day one* to stop the scheme sliding into chaos.